Opposition between a rock and a hard place
Julian Ryall in Tokyo
After a crushing defeat in last September's general election, fractious debate on its future direction and an embarrassing fiasco over a faked e-mail that has cost the Democratic Party of Japan (DPJ) president his job, the country's largest opposition party knows it cannot afford to make another mistake tomorrow.
A few more months of the sort of internal strife that has made it unelectable in the eyes of Japanese voters would surely sound the death knell for a party that until a mere seven months ago firmly believed it had a shot at power against Junichiro Koizumi, who has become the third longest-serving prime minister in Japan since the second world war.
Now, however, its remaining 196 representatives in both houses of the Diet are likely to have a choice between two men for their party's leadership, neither of whom is young or particularly charismatic. The choices are so paltry and the divisions so deep that some question whether it is even worth fighting to keep the DPJ alive.
'The feeling within the party is that we are divided and that, first and foremost, we need a leader who is stronger than the previous three presidents,' said Yukihisa Fujita, who works in the party's international division after losing his seat - along with 64 other DPJ politicians - in September. 'Some say Ichiro Ozawa is the only one who can unite the party and counter Koizumi and his successor, yet who still has the public's support,' he said. 'But there are those who say he is an authoritarian, old-fashioned politician whom the younger politicians feel could become a dictator-type leader.
'They might prefer to see Naoto Kan become leader again, but he has already lost three party presidential elections.'
As well as losing bids for the leadership, 59-year-old Mr Kan has served two brief tenures as DPJ leader, such is the merry-go-round nature of the country's opposition.
On Tuesday, he brushed aside suggestions from within the party that the two men should reach a compromise agreement to avoid a potentially divisive vote and indicated he would run. 'Choosing the leader through an election is the correct course of action. I would like to make a decision after seriously considering the voices calling for my candidacy,' he said.
Party vice-president Mr Ozawa, 63, began his unofficial campaign by saying he would 'do his utmost' to replace the ruling Liberal Democratic Party in power and the election would be 'a good opportunity to build party unity'.
A third option may see Kozo Watanabe, at 73 the party's senior man in parliament, take over as caretaker leader until the DPJ's presidential election in September.
The election was forced upon the DPJ by the decision of its president Seiji Maehara on Friday to resign to take responsibility for the e-mail controversy.
In February, DPJ member Hisayasu Nagata claimed he had an e-mail message proving that disgraced internet mogul Takafumi Horie ordered one of his staff to pay 30 million yen ($1.9 million) to the son of LDP secretary-general Tsutomu Takebe before the election.
Mr Horie is in detention on suspicion of fraud but an investigation by the DPJ quickly concluded the allegations were groundless and that the e-mail was fake. Mr Nagata resigned from the Diet on Tuesday.
'It's a farcical situation and this election is simply a matter of the party's very survival,' said Noriko Hama, a professor of economics at Kyoto's Doshisha University. 'I wonder whether anything they do will be enough to save the party because it seems to be such a hodge-podge of beliefs, with old and tired faces and names being put forward as potential leaders.
'Mr Maehara was put forward as a young and dynamic new leader and that clearly hasn't worked as the party is more divided than ever.
'Mr Ozawa seems to be the favourite and is looking slightly less tired than Mr Kan, who has enemies because he has a reputation for not listening to the rank and file,' she said.
'But frankly it would probably be better for the party to simply split up and start again. It is not a united party; it's a coalition of convenience of warring tribes.'